C#: NullReferenceException: Object reference not set to an instance of an object

Questions & Answers
1

Sorry, I realize this is a semi common question and I’ve looked at the others but can’t figure out. From what I understand, it’s telling me the script named Collectables doesn’t exist, or isn’t attached to that gameObject, but it definitely is.

I have the following script that is erroring on line 16,

collision.gameObject.GetComponent().addMint();

with the following error:

NullReferenceException: Object reference not set to an instance of an object
Collect.OnTriggerEnter (UnityEngine.Collider collision) (at Assets/Scripts/Collect.cs:16)

Here is my script:

using UnityEngine;
using System.Collections;

public class Collect : MonoBehaviour 
{
	public int type;
	// 0-Mint
	// 1-Cucumber
	// 2-Salt
	// 3-Yogurt
	void OnTriggerEnter(Collider collision)
	{
		print("type = " + type);
		if(collision.tag == "Player" || collision.tag == "Donkey")
		{
			collision.gameObject.GetComponent<Collectables>().addMint();
		
			Nasreddin temp = collision.gameObject.GetComponent<Nasreddin>();
			temp.collect(type);
			Destroy (gameObject);
		}
	}
}

I’m printing type so I know it’s being initialized, so that’s definitely happening. Also, addMint() is being called correctly, I just want to get rid of this error.

2

The issue was deeper than it appeared. My team created the object that is the Collider in this case, and they did some bad design. The player (Collider) had a nested sub-player with the typical third person scripts attached to him because the player ‘becomes’ that model at a point in the game. So the collision was happening twice - once for the thing it should, and once for the thing it shouldn’t collide with.

Bad design. Keep it out of your projects!